According to a conventional automotive engine starter, an electric motor and a magnet switch solenoid assembly are coaxially arranged in a series, and an output shaft extending coaxially from the motor is passed through the bore of the tubular solenoid assembly so that a pinion gear mounted on a free end of the output shaft may mesh with a ring gear.
In this arrangement, because the magnetic switch solenoid assembly is received in a casing which is attached to the output shaft end of the motor, the solenoid assembly is required to be fitted into the casing in the axial direction, and it is desired to simplify the assembling work for the solenoid assembly. It is possible, for instance, to use a special tool having a plurality of fingers that can be opened and closed in the radial direction. The outer peripheral part of the cylindrical solenoid assembly may be radially held by the free ends of the fingers while the solenoid assembly is being inserted into the casing. Once the solenoid assembly is placed in the casing, the fingers are opened up to release the solenoid assembly.
To secure the solenoid assembly in the casing, the casing may be provided with an annular shoulder for engaging the front end of the solenoid assembly as seen in the direction of inserting the solenoid assembly, and an annular peripheral wall surrounding the solenoid assembly. In this case, the solenoid assembly is positioned with respect to the direction of inserting the solenoid assembly by abutting the inserted solenoid assembly onto the annular shoulder surface, and is fixedly secured by crimping an axial free end of the annular outer peripheral wall onto the rear end of the solenoid assembly as seen in the direction of inserting the solenoid assembly.
However, according to this arrangement, because the parts of the fingers engaging the solenoid assembly interfere with the end portion of the annular outer peripheral wall, the solenoid assembly engaging portions of the fingers cannot keep engaging the solenoid assembly until the solenoid assembly abuts onto the annular shoulder during the process of inserting the solenoid assembly, and the solenoid assembly must be released before the completion of the process of inserting the solenoid assembly so that the solenoid assembly may not be properly positioned at the prescribed position in the casing.